Question: Simplify the following expression: $x = \dfrac{p}{10} - \dfrac{3p}{7}$
In order to subtract expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $10$ and $7$ $\lcm(10, 7) = 70$ $ x = \dfrac{7}{7} \cdot \dfrac{p}{10} - \dfrac{10}{10} \cdot \dfrac{3p}{7} $ $x = \dfrac{7p}{70} - \dfrac{30p}{70}$ $x = \dfrac{7p -30p}{70}$ $x = \dfrac{-23p}{70}$